Assembling apparatus



G. E. BERGGREN ETAL 2,404,782

July 30, 1946,

AS S EMBLING APPARATUS 3 Sheets-Sheet l i Filed Nov. 50, 1944 ERGGWEN V1 ERML AN ATTORNEY I J y 1946- G. E. BElGGREN ET AL 2,

ASSEMBLING APPARATUS Filed Nov. 50, 1944 5 Sheets-Sheet 5 F /C 8mxvavroes 85 86 as BEEGGREN A Lo AN 8) TTORMEY Patented July 30, 1946UNITED STATES PATENT OFFICE ASSEMBLING APPARATUS New York ApplicationNovember 30, 1944, Serial No. 565,840

(Cl. 292t0) 6 Claims. 1

This invention relates to assembling apparatus and more particularly toapparatus for assembling annular insulating and spacing discs on acentral conductor used in making coaxial cables.

This application is a continuation-in-part of copending application,Serial No. 470,746, filed December 31, 1942.

Coaxial cables usually comprise a solid central conductor and a tubularouter conductor, which is held away from and maintained coaxially of thecentral conductor by means of waferlike spacing and insulating discs.Such cables have been made in the past by stringing insulating discshaving central apertures therethrough upon the central conductor, muchin the same manner that beads are strung upon a strand, and then formingthe tubular outer conductor over the discs in any suitable manner. Italso has been suggested that the discs be molded directly upon thecentral conductor, but this method requires complicated and expensiveapparatus.

Another method of making these cables that has been used heretofore wasto punch a number of insulating discs from a strip of suitable material,such as hard rubber, in a punch press having a punch and die of suchconfigurationthat the discs had central apertures for receiving thecentral conductor and radial slots extending from the central openingsto the periphcries of the discs through which the central conductor wasforced into the central openings. Usually the radial slots hadconstricted portions, and the discs were sufficiently resilient topermit the slots to open up as the central conductor passed through theconstricted portions and to snap back around the conductor after theconductor had entered the central apertures in the discs. As a result,the discs engaged the central conductor firmly and could not bedisplaced readily.

Polystyrene has been suggested as a suitable material to use in makingthe insulating discs, but pure polystyrene is so brittle that slotteddiscs made therefrom cannot be applied to central conductors withoutbreaking the discs. Hence, when polystyrene discs are used they must bethreaded or molded upon central conductors. It is obvious that whenlong, con tinuous central conductors are employed, it is impractical tothread centrally perforated discs upon such conductors, while apparatusfor con tinuously molding discs upon such central conductors is costlyand complicated.

The application of slotted discs to central conductors may be performedwith satisfactory results when the discs are made of a relatively hard,resilient material, such as hard rubber, but this method isunsatisfactory when discs made of soft plastics are employed.

One of the plastic materials, which has properties that renderinsulating discs made therefrom especially suitable for use in themanufacture of coaxial cables, is the one obtained by polymerizingethylene. This material, which is called polyethylene, is a moderatelysoft, pliable material, having a high molecular weight and possessingexcellent insulating characteristics. This material may be obtained fromseveral sources, one of which is E. I. Du Pont ole Nemours & Company,which sells it under the trade name Polythene.

Polyethylene is sufficiently hard to permit insulating discs madetherefrom to maintain their shapes under ordinary circumstances, but itis soft enough to cause some manufacturing difficulties to arise whenslotted discs are punched from strips thereof, Furthermore, when slotteddiscs of the type formerly made of hard rubber were made of polyethyleneand were forced upon a central conductor, the sides of the slotsoccasionally were deformed by the passage of the conductor therethrough.As a result, the discs would not adhere firmly to the central conductor,and would tend to slide along the conductor or might even come off theconductor. In addition, it is relatively easy to force such discs on theconductor by a thrust applied on the sides of the discs opposite theslots and substantially longitudinally of the conductor, because thesmall amount of the material in the Walls of the slots against which theconductor presses under those circumstances does not possess enoughsheer strength to hold the discs in place.

An object of the invention is the provision of simple and effectiveapparatus for assembling articles.

An apparatus embodying the invention operates as follows: a singlehopper feeds annular insulating discs through two sets of separate feedpaths to a pair of feed wheels, which carry the discs past knives to cuta radial slit in each annular disc and which alternately slide the discsupon a constantly moving central conductor with a wiping motion, theslits in the discs being held slightly openand maintained in the slotsin the feed wheels by means of retus for applying annular insulating andspacing .discs to a central conductor, which apparatus embodies theapparatus of the present invention and provides means by which thepresent invention may be practiced;

Fig. 2 is an enlarged, fragmentary, detailed sectional view takensubstantially along the line 2-2 of Fig. l in the direction of thearrows;

Fig. 3 is an enlarged, fragmentary, sectional View taken substantiallyalong the line 3-3 of Fig. 1 in the direction of the arrows;

Fig. 4 is a fragmentary, sectional view taken substantially along theline 4-4 of Fig. 3 in the direction of the arrows and showing details ofone of the feed wheels and its co-operating parts;

Fig. 5 is a'greatly enlarged detailed View in section takensubstantially along the line 5-5 of Fig. 4 in the direction of thearrows and showing an insulating disc being carried by a feed wheel,together with the retainer provided for holding the discs on the feedwheel and for holding open the slits in the discs;

Fig. 6 is a fragmentary plan view, partly in section, of the hopper andits communicating disccarrying mechanisms for directing the annulardiscs to the feed wheels;

Fig. 7 is an enlarged, fragmentary, vertical, sectional view takensubstantially along the line 1-1 of Fig. 6 in the direction of thearrows;

Fig. 8 is a detailed, elevational View showing a knife for slitting theinsulating discs;

Fig. 9 is an enlarged, fragmentary perspective view'of the blade end ofthe knife shown in Fig. 7 and illustrating how the knife cuts slits inthe annular discs;

Fig. 10 is a detailed view showing one of the annular discs before it isslitted;

Fig. 11 is a cross-sectional view of a coaxial cable utilizing the unitcomprising the central conductor and insulating discs assembled inaccordance with the present invention, and

Fig. 12 is a view in perspective of a short length of coaxial cable,which utilizes the unit formed in accordance with the present invention,part of the tubular outer conductor being broken away to illustrate thepositioning of the insulating and spacing discs between the tubularouter conductor and the central conductor.

Referring to the drawings, wherein like reference characters designatethe same parts throughout the several views, a main support member [5 isprovided for supporting a hopper designated generally by the numeral 16,feed wheels I! and I8 and transfer devices designated generally by thenumerals l9 and 20. The hopper l5 and the transferdevice 9 areinterconnected by a-guide designated generally by the numeral 2| and thehopper l6 and transfer device are interconnected by a guide designatedgenerally by the numeral 22. The details of the hopper l6 are shown mostclearly in Figs. 6 and 7 and, by reference to these figures, it will beseen that the hopper includes an inverted cone-shaped bin 23, intowhichannular discs may be dropped haphazardly. The bin 23 terminates atits lower end in an annular member 24 surrounding a substantiallycone-shaped agitator 25. The agitator 25 may be rotated within theannular member 24 in any suitable manner, for example, by a motor (notshown) driving a transmission or gear reducing unit 26, which alsosupplies power to drive a pair of shafts 21 and 28 on which the feedwheels H and I8 are mounted. This driving connection may be of anysuitable construction and, since the details thereof are not pertinentto the present invention, they have not been described in great detail.

Extending upwardly from the unit 26 is a shaft 29, on which the cone 25is supported for rotation within the bin 23. The cone 25 is providedwith a flattened cylindrical lower end 30, which, together with the bin23, defines an annular slot 3| into which annular discs 32-32, as shownin Fig. 7, may drop when the agitator 25 is rotated within the bin 23.Fixed to diametrically opposed surfaces of the agitator 25 area pair offeed fingers 33 and 34 made of steel wire and bent to extend into theannular slot 3| formed by the annular member 24 and the flattened lowersurface of the agitator 25, whereby any discs which drop into the slotmove around in the slot as the agitator 25 rotates. The feed fingers 33and 34 are sufficiently resilient so that if the guides 2| and 22 arefilled with discs, the feed fingers'will bend and pass over the tops ofthose discs in the slot 3 I.

At opposite sides of the annular member 24, there are provided means fordirecting discs 32-32 from the slot 3| into the guides 2| and 22 andthese devices comprise support plates 4|] and 4| fixed to the annularmember 24 and carrying assemblies 42 and 43, respectively, for directingthe discs into the guides 2| and 22. Both of the assemblies 42 and 43are of exactly the same construction and, accordingly, only the assembly42 will be described in detail. The assembly 42 comprises two plates 44and 45 suitably fixed together iri abutting relation. The plate 45 has agroove 46 formed therein which, when the assembly 42 is mounted inplace, as shown in Figs. 6 and 7, comprises a tangential prolongation ofthe annular slot 3|. The groove 46 cooperates with the flat surface ofthe plate 44 to form a passageway into which the discs 32-32 will bedirected by an extending finger 45, which is formed integrally with theplate 45 and extends into an annular slot 48 formed on the flat lowersurface of the cone-shaped agitator 25. The finger 41 serves to stripthe discs out of the slot 3| and guide them into the groove 46. Theannular member 25 is cut away, as shown at 49 and 50, to receive theplates 44 and 45 so that the plates 44 and 45 will cooperate to guidethe discs into the guides 2| and 22.

The guides 2| and 22 are of the same general construction except thatthey are bent at different angles for guiding the discs 32-32 fedtherein from opposite sides of the hopper I6. Each of the guides 2| and22 comprises, as shown most clearly in Fig. 2, a strip 5| having a slot52 cut therein, in which the discs 32-32 will drop. At-

tached to the strip 5| is a thin plate 53, which,

partially closes the slot 52 and will serve to retain the discs inposition therein while they are guided down from the hopper to thetransfer devices I9 and 20. A slit between the plate 52 and strip 5|permits visual inspection of the supply of discs 32-32 in the guidesand, if desired, air blasts may be directed against the discs to insurethat they move down the guides.

At the transfer devices 19 and 23, the guides 2| and 22 terminate in atransfer block 60, which has a slot 6| formed therein, which slotcomprises a prolongation of the slot .52 in the strip 5|. The slot 61 isin communication with a plunger slot 62, in which a plunger 63 isslidably mounted. The plunger 533 is mounted upon a connecting member64, which is formed integrally with a cam projection 65, A spring 56normally urges the camming projection 65 and connecting member 64 to theleft, as seen in Fig. 2, to carry the camming projection 5.5 intoengagement with a cam 61. The cam 57 is mounted upon the shaft 28 and ispositioned in back of the main support member l5. The shaft 25 alsocarries a gear 63 in mesh with a gear 59 fixed to the shaft .2! and theshaft 2'! also carries a cam member 153 of exactly the same constructionas the cam 61. Thus, the construction is the same for both transferdevices [9 and 20.

A plate 1'! 8 fixed to the main support member l5 serves as a guide forthe connecting member 64 and the main support member I5 is provided witha suitable aperture '22, which permits the connecting member 64 andcamming projection 65 to reciprocate in a guide slot 73 formed in theplate ll. Each time the camming projection .65 strikes a low point onthe .cam 6 one of the discs 32-32 will be transferred from the slot 6|into the feed wheel l8, which is provided with a series of notches i l-Mfor receiving the discs It should be noted that the notches 74-74alternate with notches iii-i5 around the periphery of the feed wheel l8and that the notches '55-'55 have one surface cut awa for a purpose to bdescribed i hereinafter.

As the feed wheel i8 rotates, an annular disc 32 will be fed into eachof the notches Hi-H. cut therein and will be carried around with thefeed wheel I13. Just below the position where the feed wheel !8 receivesthe annular discs 32-3-2, there is provided a knife l6 (Figs, 4, 8 and9), which will cut a radial slit 7'! (Figs. 9, 11 and 12) in each discas the di cs are carried past the knife. Extending peripherally of thefeed wheel lBin direct vertical alignment with the knife i5 is aretainer l5, with which the slit l! in each annular disc will engage andwith which the edge of the central aperture iii of each disc will engage(Figs. 4 and 5), whereby the disc 32-52 will be forced to travelaronndwith the feed wheel IS. The retainer 18 extends to a positionWhere it is engaged on its upper edge by a central conductor 85, onwhich the discs 32-32 are to be assembled. The retainer 73 has the samethickness as the bottom portion of the knife l5 and the discs which areslit by the knife pass directly from the knife onto the retainer. Theretainer holds the slits formed in the discs slightly open until thediscs reach the central conductor 80, which permits the centralconductor to slid -freely into and through the slits into the centralapertures Iii-l2 in the discs.

The central conductor 88 is fed through a guide 8|, which cooperateswith other guides and feed mechanisms (not shown) for guiding theconductor past the feed Wheels I1 and I8 in timed relation to therotation of the feed wheels. The construction of the slitting mechanismat the transfer device 29 is exactly the sameas at the transfer devicel9, lf'here is provided a knife similar to the knife '56 for slittingthe discs radially and a retainer 82 similar to the retainer 18, butshorter than the retainer 13, for guiding those discs 32-32 which arefed to the feed wheel I! 6 to a position where the discs will be forcedonto the central conductor 80 and. for holding open the slits in thediscs until they reach the central conductor. The feed wheel H isprovided with notches 14-14 and -15 alternately about its periphery inthe same manner as is the disc is, since it is desired to apply thediscs 32-32 from opposite sides of the central conductor 82. When atubular outer conductor'83 is applied around the discs 32-32 co-axiallywith the central conductor 853, the discs 32-32 will hold the tubularouter conductor spaced an equal distance from the central conductor 89throughout the length of the cable and will insulate th two coaxialconductors from each other.

As is evident from Figs. 8 and 9, each of the knives illustrated by theknife 76 comprises a flat shank 88 having a head 84 formed at the endthereof adjacent to its companion feed wheel.

The bead 84. has a raised point 65 at the top 1 thereof designed tocause the bead to enter the central apertures 12-79 of the discs 32-32so that a curved cutting edge 86, which is formed at the upper edge ofthe shank and extends from the point 8 5 to a point on the shank beyondthe outer edges of the discs, may cut a radial slit 7'! in each disc athe discs 32-32 are carried past the knives by the feed wheels.

Since the discs 32-32 are applied to the central conduct-or fromopposite sides, the notches 14-14, which carry the discs 32-32 on bothof the feed wheels I! and I8, are arranged so that when one of the discs32-32 is forced onto the central conductor 80 b the feed wheel l8, oneof the notches 15-15 in the feed wheel I! will receive the upper end ofthe disc. Likewise, when the feed wheel I1 carrying a disc 32 in one ofits notches i l-l4 reaches the position where the disc is to be forcedonto the central conductor, the notch Min the feed Wheel I! whichcarries the disc will be in alignment with a notch 15 on the feed wheell8 and the latter notch will receive the disc.

In the operation of the present machine a supply of annular insulatingand spacing discs 32-32 may be thrown haphazardly in the hopper ts, fromwhich they will be fed by the feed fingers 34 and 35 into the guides 2iand 22. As the discs 32-32 ar fed into the guides, they will travel downthe guides to the transfer devices I9 and 23 and the cams l5! and H1,operating in timed relation with each other, will transfer the discsinto th notches 14-14 of the feed wheel I! and 13. As the discs arecarried around by the feed wheels H and [8, they will be drawn past theknives, illustrated by the knife l6, and a radial slit will be cut ineach discby the knives, The slitted discs will then be carried around bythe feed Wheels ii and I2, being held in the notches Id-i4 by theretainers 82 and 78, until the slitted discs are forced onto the centralconductor 85 travelling from left to right as seen in Fig. 1. After thediscs 32-32 are thus applied to the central conductor 89. the tubularouter conductor 83 may be applied over the discs in any suitable manner.

As is apparent from Figs. 4 and 5, the retainers l3 and 82 maintain theslits ll-Tl in the discs 32-32 slightly open from the time the slits arecut therein by the knives until the discs reach the central conductor 89upon which they are applied. This permits the central conductor 59 toenter the slits readily and to slide easily through the slits into thecentral apertures ls-l9 of the discs. The discs 32-32 are carried towardthe central conductor by the feed wheels l1 and 18 along arcuate pathsand, consequently, the discs are forced upon the central conductor witha wiping motion. In view of the fact that the slits H are held slightlyopen by the retainers l8 and 82 until the discs reach the centralconductor 80 and also because the discs are applied to the centralconductor with a wiping motion, no injury results to the forward cornersand sides of the slits, such as might occur if the slits were permittedto close before they reach the central conductor and were forciblyopened by the passage of the central conductor therethrough. This isespecially important when the insulating discs are made of relativelysoft materials, such as polyethylene.

Since the retainers l8 and 82 end at a point adjacent to thecentralconductor 80, the slits are released as the discs are applied to thecentral conductor and are free to close after the discs have been placedupon the central conductor. As a result, the slits tend to close up andthe discs substantially completely surround the central conductor,somewhat in the manner illustrated in Figs. 11 and 12, thereby insuringthe retention of the discs in their proper places upon the centralconductor.

The central apertures 19-19 in the discs 3232 are slightly smaller indiameter than is the central conductor Bil. As a result, the centralconductor tends to spread open the slits ll'll in the discs, as is shownin Fig. 12, and the natural resiliency of the discs causes the discs toengage the central conductor firmly. After the tubular outer conductorhas been applied over the unit formed by the central conductor and aseries of discs applied thereto, the slits in the discs aresubstantially closed, as shown in Fig. 11, and then there is practicallyno possibility that the discs will slide along the central conductor.

The apparatus outlined hereinabove obviates the problems that wouldarise if an attempt were made to slit the discs at the time the areformed, to feed the slitted discs from a hopper into a pair ofmechanisms with the slits orientated and to advance the discs throughthe mechanisms to the applicator Wheels. Likewise, deformation of thewalls of the slits is prevented and the discs so applied to a centralconductor engage the conductor firmly. It is diflicult to purposelyremove discs thus applied to the conductor, much less to remove themaccidently, because the slits tend to close up around the conductor andthe conductor is engaged by a substantially solid ring of insulatingmaterial, such as is illustrated in Figs. 11 and 12 of the drawings. Itis obvious that the location of the slitting step is important and thatthis invention provides a simple yet elTective apparatus for assemblingarticles, particularly apparatus for the application of insulating discsto central conductors to form units suitable for use in the manufactureof coaxial cables.

While the insulating discs 32 32 preferably are made of polyethylene,the apparatus embodying the invention may be used equally well to applydiscs made of other relatively soft insulating materials to centralconductors. For example, the insulating discs may be made of celluloseacetate or mixtures of cellulose acetate and cellulose butyrate, or maybe fabricated from relatively soft products obtained by polymerizingvinyl compounds, such as are obtained by polymerizing vinyl chloride andvinyl acetate or mixtures thereof.

What is claimed is:

1. In an apparatus for applying soft annular discs to a conductor, meansfor feeding a plurality of such discs along a predetermined path and toa conductor, and means adjacent to said path including means for cuttingeach of the annular discs advanced therealong to form discontinuousannuli, means passing through the resulting cuts in the discs forexpanding the cuts and means entering the expanded cuts for maintainingthem expanded, said last mentioned means extending to the conductor,whereby the conductor slides freely through the expanded cuts withoutdamaging the discs.

2. An apparatus for use in applying soft annular discs to a conductor,comprising a guide for receiving slitted discs along one side thereofand for guiding the discs to a conductor, the guide being thinner thanthe diameter of the conductor and being received in the slits in thediscs to hold them open, and means in advance of the guide for formingslits in the discs which have a gap no wider than the thickness of theguide, said slitting means including means for expanding the slits inthe discs and while the slits are expanded guiding the discs to theguide.

3. An apparatus for applying soft annular insulating discs upon aconductor, which comprises a rotatable feed wheel for advancing suchdiscs to and forcing them upon the conductor, means for cutting slits inthe discs carried by the feed wheel and for expanding the slits, andmeans adjacent to the slit-cutting means for entering the expanded slitsin the discs and for maintaining the slits expanded until the discs areadvanced to theconductor.

4. An apparatus for applying soft annular insulating discs upon aconductor, which comprises means for longitudinally advancing theconductor, a rotatable feed wheel for advancing such discs to andforcing them upon the movingconductor, a knife adjacent to the feedwheel and in the path of discs carried by the feed wheel for cuttingradial slits in the discs and for expanding the slits, and an arcuateretainer adjacent to the knife and in alignment therewith for enteringthe expanded slits and keeping them expanded until the discs reach theconductor. J

5. In an apparatus for applying soft annular insulating discs upon aconductor, means for advancing a plurality of such discs along apredetermined path to the conductor, a knife extending into said pathfor cutting radial slits in the discs advanced therealong, said knifehaving a cutting edge of reduced thickness on the side thereof firstengaged by the discs and expanding to a greater thickness at the edgewhere the discs leave the knife, and a guide abutting the exit edge ofthe knife for entering the slits cut in the discs as the discs leave theknife to prevent the slits from closing, said guide extending to theconductor.

6. An apparatus for applying soft annular insulating discs to aconductor, which comprises means for advancing a conductorlongitudinally,

rotatable feed wheels fOr carrying such discs to opposite sides of theconductor and forcing them upon the conductor, means for feeding thediscs to the feed wheels, a knife associated with each feed wheel andpositioned in the path of the discs carried by its associated feed wheelfor cutting radial slits in said discs, each of said knives having acutting edge of reduced thickness on the V e 10 Side th re f first en aed y the discs and exfrom closing and extending to a point close topanding to a greater thickness at the edge where the conductor, wherebythe conductor slides freethe discs leave the knife, and an arcuateretainer 1y through the slits Without damaging the discs. adjacent toeach feed Wheel and abutting the exit edge of the associated knife, eachof said GEORGE E. BERGGREN. guides entering the slits cut in the discsas the EDWARD BERTALAN. discs leave the adjacent knife to prevent theslits ALEXANDER LOGAN.

